Function at the Level of C3


What Motor Function is Consistent with C3?
  • The nerve root of C3 runs between vertebrae C3 and C4. 
  • Motor function includes:
    • weak diaphragm
    • usually unable to sustain ventilation
    • weak neck movement (sternocleidomastoid present, weak trapezius) 
What Sensory Function is Consistent with C3?
  • C3 provides sensation for lower neck. 
Assessment of C3 Motor Function
  • Evaluate ability to contract neck muscles (NOTE: cervical spine immobilization limits ability to assess during acute phase).
  • Place examiner's hand over trapezius and ask patient to shrug shoulder.  Assess motor function.  C3 function will provide only weak neck function.
  • Assess ability to turn cheek from side to side (sternocleidomastoid). NOTE: only assess after cervical immobilization has been discontinued.  Muscle strength can be assessed by having patient turn cheek against examiner's resistance.
Assessment of C3 Sensory Function
  • Test one side, then test same spot on opposite side
  • Always apply the same amount of pressure to each side
  • Ask patient to compare sensation on side A to side B
  • Conceal test from the patient
    • Light touch:
      • use wisp of cotton or tissue; touch neck on either side and assess sensation
    • Sharp or temperature touch:
      • use safety pin, cap of pen or ice cube (do not use needle); assess neck on either side
Expected Outcome
  • swallowing
  • speaking
  • usually ventilator dependent 

Brenda Morgan
Clinical Educator, CCTC
May 11, 2001

Barr, M, and Kiernan, J. (1993). The Human Nervous System: An Anatomical Viewpoint. Philadelphia: Lippincott. pp 84-85.

Keppler, J. (1987). Acute spinal cord injury. Critical Care Clinics. July. 3:3. pp. 638-641.

Netter, F. (1989). Atlas of Human Anatomy. New Jersey: Novartis.

Waxman, S. (1996). Correlative Neuroanatomy. 23rd Ed.  Stamford: Lange. pp 46-52, 352-355, 370.


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Last Updated March 31, 2009 | © 2007, LHSC, London Ontario Canada